More so than other early 1970s operating systems, SCOPE/Hustler featured an interactive service which was closely integrated with its batch service. At the time, it was common for an interactive subsystem to have a different command and feature set than batch service. SCOPE/Hustler's interactive service was sometimes known as MISTIC 2. (The original MISTIC, which stood for MIchigan STate Integral Computer, was a tube-based computer built at MSU based on plans from the University of Illinois.) But perhaps because interactive service wasn't that much different than batch, it was rare to refer to interactive logins by this separate name.
About the only batch feature not available interactively was magnetic tapes. The tape drives were heavily used, and we couldn't afford to have them tied up by interactive users.
All interactive I/O went through MANAGER, a CPU program that ran at control point 1. Manager had a helper PP program named MGR. Raw I/O to and from the Interdata Front-end was handled by 1FP. I can't recall the relationship amongst MANAGER, MGR, and 1FP; it is possible that MANAGER and 1FP exchanged information directly, bypassing the middle-man in most instances.
The front-end intercepted and executed FREND commands, lines which typically began with the % character. All other commands were passed to MANAGER for parsing. For most commands,
Connected files. Display code vs. ASCII vs. BI. TTYTTY.
MSU developed a text editor that was integrated with the interactive system, and yet could be used in batch mode if necessary. See MSU EDITOR.
Notes to myself:
MISTIC, EDITOR, $editor. MISTIC: OK/READY. +localfile